BIDIRECTIONAL DECODING OF CONVOLUTIONAL-CODES FOR INDOOR CELLULAR RADIO

Bidirectional suboptimal breadth-first decoding of convolutional codes is an attractive technique for slowly varying and quasi-static fading channels as it restricts the extent of decoding errors due to correct path loss to very heavy noise or interference regions. This paper com pares the performance of such a decoding scheme to the Viterbi algorit hm over wide-band TDMA indoor radio links where equalization and space diversity are also used to combat dispersive fading and cochannel int erference. On the basis of equal computational complexity and equal de coding delay, suboptimal, breadth-first, bidirectional decoding of a l ong constraint length convolutional code is shown to be superior to Vi terbi decoding of a shorter constraint length code. Furthermore, this advantage increases as the outage criterion (in terms of bit error rat e) becomes more stringent which makes bidirectional decoding particula rly attractive for data applications and makes channel coding a more a ttractive alternative to increasing the space diversity order at the r eceiver.